The Helios 2 system includes Helios 2A and Helios 2B, both of which are European military observation satellites used by France, Belgium, Spain and Greece.[1] Helios 2A was launched on December 18, 2004 by an Ariane 5 rocket from French Guiana. Helios 2B was launched five years later on December 18, 2009, carried also by an Ariane 5. The two satellites are identical.[2] They carry a Thales-built high-resolution visible and thermal infrared instrument with 35 cm resolution,[3] and an Airbus-built medium-resolution instrument.[4]